Semiconductor structure and semiconductor laser device

Abstract

A semiconductor structure has a substrate crystal having a plurality of crystal orientations. Above the substrate is an atomic-layer superlattice in which different semiconductors are laminated one over another with a period in terms of atomic layers. This structure makes it possible to realize a semiconductor structure in which several kinds of quantum wires or quantum boxes having different physical properties, or an atomic-layer superlattice having an enlarged structure of the quantum wire or quantum box, are arranged in the plane orientation of the same substrate. In addition, the structure makes it possible to realize a semiconductor laser device having this structure.

What is claimed is: 
     
       1. A semiconductor structure which has a substrate crystal having a plurality of crystal orientations and above said crystal is an atomic-layer superlattice in which different semiconductors are laminated one over another with a period in terms of atomic layers and which is made up of semiconductor layers each having a thickness of 1-atom to 5-atom layer, with at least a part of said atomic-layer superlattice having a different band gap than the remainder. 
     
     
       2. A semiconductor structure as claimed in claim 1, in which the crystal orientation includes at least one plane selected from the group consisting of the (100) plane and the (111) plane. 
     
     
       3. In a semiconductor laser device which has, above a substrate, two cladding layers and one active layer interposed between said cladding layers, said substrate being a substrate crystal having two (100) planes and at least one (111) plane arranged between said two (100) planes, at least one layer selected from the group of said two cladding layers and one active layer being an atomic-layer superlattice in which different semiconductors are laminated one over another with a period in terms of atomic layers and which is made up of a semiconductor layers each having a thickness of 1-atom layer to 5-atom layer and a portion thereof corresponding to said active region has a refractive index larger than that of the remainder of said active region, and a light emitting active region in said active layer being above said (111) plane. 
     
     
       4. The device of claim 3, in which at least one layer of said cladding layers is said atomic-layer superlattice and the portion thereof corresponding to said active region has a refractive index larger than that of the remainder. 
     
     
       5. The device of claim 4, in which said active region consists of one (111) plane, said cladding layers and active layer are said atomic-layer superlattice and the portions thereof corresponding to said active region each has a refractive index larger than that of the remainder. 
     
     
       6. The device of claim 3, in which said substrate crystal corresponding to said active region has a plurality of (111) planes and a plurality of (100) planes arranged between said (111) planes, said active layer is said atomic-layer superlattice and said active region consists of quantum wire structure. 
     
     
       7. The device of claim 6, in which said cladding layers are also said atomic-layer superlattice.